KR101152996B1 - Radio communication system, transmission device, reception device, radio communication method - Google Patents

Abstract

One of the objectives of the present invention is to control the MCS of retransmission data and normal data independently without departing from the standard, and to effectively utilize adaptive modulation and improve the stability of wireless communication by using MCS suitable for each data. It is. In the wireless communication system 100 of the present invention, since both the transmission device and the reception device specify a frame and an error portion in which an error occurs, the MCS used for the frame is specified, so that the desired MCS does not need to be placed on the HARQ. The error part can be demodulated based on.

Description

Wireless communication system, transmitting device, receiving device, wireless communication method {RADIO COMMUNICATION SYSTEM, TRANSMISSION DEVICE, RECEPTION DEVICE, RADIO COMMUNICATION METHOD}

The present invention relates to a wireless communication system, a transmission device, a reception device, and a wireless communication method capable of wireless communication by adaptive modulation (high speed adaptive modulation).

In recent years, mobile stations typified by PHS (Personal Handy phone System), cellular phones, and the like have become widespread, and call and information can be obtained regardless of the place and time. In recent years, the amount of information available has also increased, and a high-speed and high-quality wireless communication system has been acquired in order to download a large amount of data.

For example, next-generation PHS communication standards that enable high-speed digital communication include Association of Radio Industries and Businesses (ARIB) STD T95 or PHS Memorandum of Understanding (MoU). In such communication, Orthogonal Frequency Division Multiplexing (OFDM): Orthogonal frequency division multiplexing has been adopted. Such OFDM is classified as one of multiplexing schemes, and by using a plurality of carriers on a unit time axis, the bands of carrier waves are partially overlapped with each other such that phases of signal waves to be modulated are orthogonal to neighboring carriers to effectively use frequency bands. That's the way.

Orthogonal Frequency Division Multiplexing (OFDMA), in which a plurality of users share all subchannels and allocate the most efficient subchannel to each user, while OFDM allocates subchannels by time division for each user. Access (orthogonal frequency division multiple access) is also provided.

In the ARIB STD T95 or the PHS MoU, a modulation scheme and a coding scheme (MCS: Modulation and Coding Scheme (MCS), hereinafter simply referred to as MCS) determined by adaptive modulation are FM-mode (Fast access channel based on Map-Mode) (for example, For example, by transmitting to the transmission apparatus via the anchor channel in Non-Patent Document 1), the transmission apparatus modulates the data based on the MCS, thereby performing communication using the MCS that is optimal in the communication environment at that time. Can be.

This adaptive modulation estimates the communication environment between the transmitting device and the receiving device based on the signal to interference and noise ratio (SINR) or bit error rate of the uplink communication signal transmitted from the mobile station to the base station. In a good communication environment, an MCS that exhibits a higher modulation efficiency is selected, and in a situation where the communication environment is poor, an MCS that exhibits a low modulation efficiency is selected to enable stable wireless communication.

In addition, in ARIB STD T95 or PHS MoU, when a receiving device receives wrong data, an automatic retransmission request (ARQ: Automatic Repeat reQuest, hereinafter simply referred to as ARQ) requesting the transmitting device to retransmit the data is received. Is sent. Since the transmitting apparatus retransmits the data to the MAC layer (low layer) for such ARQ, the error can be efficiently compensated for with a short control time (Non-Patent Document 2). In addition, in ARIB STD T95 and PHS MoU, a combination of such ARQ and Forward Error Correction (FEC) is used, and HARQ (Hybrid ARQ) technology is further employed to further improve packet error correction efficiency.

Non-Patent Document 1: ARIB (Association of Radio Industries and Businesses) STD-T95 Non-Patent Document 2: A-GN4.00-01-TS Rev. 3 Next Generation PHS Specifications, P331-340

In the ARIB STD T95 and the PHS MoU, data to be transmitted and received is divided into frame units, and the MCS may be set for each minimum unit of data (PRU: physical resource unit, hereinafter simply PRU) in the transmission frame. However, the amount of information allocated to the MCS is enormous and occupies the data area unnecessarily. Therefore, in consideration of the fact that data of one frame is transmitted at almost the same time, in this standard, the MCS is designated only once for all the frames.

However, in the above-mentioned ARQ, the MCS of the retransmitted data must be the same as when it was transmitted last time, and only one type of MCS can be specified for one frame, so that all data of the frame including the retransmission data is Regardless of the propagation environment at that time, it was fixed to the MCS of retransmission data.

Then, the optimal MCS acquired from the receiving terminal to transmit normal data other than the retransmission data of the frame is canceled, and the benefit of the adaptive modulation cannot be obtained, and the communication speed is too high by the MCS of the retransmission data. Or, it may be too late to cause a new error in the normal data, and the error correction operation ARQ may cause the error.

In order to avoid this problem, it is possible to disable the ARQ in the ARIB STD T95 or the PHS MoU and to correct the error to the upper layer. However, by not using an ARQ that efficiently compensates for errors with a short control time, the error correction time is prolonged.

In view of such a problem, the present invention independently controls the MCS of retransmission data and normal data without departing from the standard, and uses MCS suitable for each data, thereby effectively utilizing adaptive modulation and improving the stability of wireless communication. It is an object of the present invention to provide a radio communication system, a transmission device, a reception device, and a radio communication method capable of being designed.

In order to solve the above problems, a representative configuration of the present invention is a transmission apparatus for transmitting data in units of frames modulated based on MCS determined by adaptive modulation and an MCS identifier capable of specifying an MCS, and wireless communication with the transmission apparatus. A wireless communication system including a receiving device for demodulating data received on the basis of an MCS specified by a received MCS identifier, wherein the transmitting device specifies a data frame by using an MCS identifier of an MCS that modulates data and data to be transmitted. A transmission data holding unit held in association with a possible frame identifier, a data modulation unit for modulating data based on the held MCS, and a data transmitter for sequentially transmitting the modulated data; A data receiver for receiving data, a data demodulator for demodulating the received data, and a demodulator An error detection unit for detecting an error in the data, a demodulation data holding unit for holding the MCS identifier of the demodulated data and the data in association with the frame identifier when an error is detected in the demodulated data, and an error in the demodulated data. And an ARQ transmitter for transmitting an ARQ (automatic retransmission request) including a frame identifier of the data and an identifier of the error portion, wherein the data modulator comprises a frame identifier of the ARQ and an identifier of the error portion after a predetermined frame from the reception of the ARQ. On the basis of the MCS held in the transmission data holding unit, the error portion of the data held in the transmission data holding unit specified by M is modulated based on the MCS determined by the adaptive modulation, and the data transmitting unit modulates the data. The data is retransmitted, and the data demodulator retains the error portion of the received data in the demodulation data holding unit. Based on the MCS, the data other than the error portion is demodulated based on the MCS determined by adaptive modulation, and the receiving apparatus further includes a chase synthesis section for chasing the demodulated error portion and the data held in the demodulation data holding portion. Characterized in that. The radio communication system is a system based on ARIB STD T95 or PHS MoU, and the ARQ may be HARQ in the radio communication system.

Under the FM-mode in the wireless communication system, only one type of MCS can be designated for one frame. However, since retransmission of the error portion is performed at a predetermined frame timing, if both the transmitting apparatus and the receiving apparatus can identify the frame in which the error occurs and the error portion, and can identify the MCS used in the frame, ARQ or Even if the MCS is not placed on the HARQ, the error part can be demodulated based on the desired MCS. Therefore, the required area of the MCS can be released from the normal data, and the MCS based on the adaptive modulation can be set to the normal data. In this way, by independently controlling the MCS of the retransmitted data and the normal data, and using the MCS suitable for each data, it is possible to effectively utilize adaptive modulation and to improve the stability of wireless communication.

The data modulator may modulate the error portion of the data retransmitted by ARQ or HARQ at a predetermined position in the frame.

This configuration makes it possible to intensively arrange the PRUs of the same error portion in the MCS at a predetermined position irrespective of the arrangement or the number of error PRUs in the retransmitted frame, thereby reducing the burden of modulation processing. .

The MCS in the data modulator may be the same as the MCS requested by the receiver or an MCS that is inferior in modulation efficiency.

With such a configuration, the data can be modulated based on an MCS that is less than or equal to the MCS requested by the receiving device and can be modulated by the transmitting device, and is optimized for both the receiving device and the transmitting device. By this, more stable wireless communication can be established.

According to another aspect of the present invention, there is provided a transmitting apparatus for transmitting to a receiving apparatus an MCS identifier capable of specifying data and an MCS in a frame unit modulated based on an MCS determined by adaptive modulation. A transmission data holding unit for holding the MCS identifier in association with the frame identifier of the data, the data modulation unit for modulating the data based on the held MCS, and a data transmitter for sequentially transmitting the modulated data; When receiving an ARQ (automatic retransmission request) from the receiving apparatus, the data modulating unit receives the data held in the transmission data holding unit specified by the frame identifier of the ARQ and the identifier of the error part after a predetermined frame from the reception of the ARQ. Based on the MCS held in the transmission data holding part, the error part specified by Modulate the data based on MCS determined by adaptive modulation, and data transmission is characterized in that to re-transmit the modulated data.

By such a configuration, the transmission apparatus modulates retransmission data and normal data independently based on the MCS suitable for the respective data without departing from the standard, thereby enabling effective utilization of adaptive modulation and improved stability of wireless communication. Can be.

According to another aspect of the present invention, there is provided a receiving apparatus for receiving, from a transmitting apparatus, data of a frame unit modulated on the basis of MCS determined by adaptive modulation and an MCS identifier capable of specifying an MCS, comprising: a data receiving unit receiving data from the transmitting apparatus; And a data demodulation unit for demodulating the received data, an error detection unit for detecting an error of the demodulated data, and an MCS identifier of the demodulated data and data in association with the frame identifier when an error is detected in the demodulated data. And an ARQ transmitter for transmitting an ARQ (auto retransmission request) including a frame identifier of the data and an identifier of an error part when an error is detected in the demodulated data. Based on the MCS held in the demodulation data holding unit, the error portion of the data received from the And a chase synthesis section for demodulating on the basis of the MCS determined by the adaptive modulation and chasing the demodulated error portion and the data held in the demodulation data holding section.

With this configuration, the receiving device demodulates the retransmission data and the normal data independently based on the MCS suitable for the respective data without departing from the standard, so that the effective use of the adaptive modulation and the stability of the wireless communication can be improved. Can be.

According to another aspect of the present invention, there is provided a transmission apparatus that transmits data in frame units modulated based on MCS determined by adaptive modulation and an MCS identifier capable of specifying an MCS, and an MCS identifier capable of wireless communication with the transmission apparatus and received. A wireless communication method for performing wireless communication using a receiving device that demodulates data received on the basis of a specified MCS, wherein the transmitting device is capable of identifying a frame of data by using an MCS identifier of an MCS that modulates the data and data to be transmitted. Retains in association with the frame identifier, modulates data based on the retained MCS, sequentially transmits the modulated data, and the receiving device receives data from the transmitting device, demodulates the received data, and demodulates the data. Error in the demodulated data, and if the error is detected in the demodulated data, Keeps associated with a random identifier, and transmits an ARQ (auto retransmission request) including a frame identifier of data and an identifier of an error portion, and the transmitting apparatus also sends a frame identifier and an error portion of the ARQ, after a predetermined frame from the reception of the ARQ. Based on the retained MCS, the error portion of the retained data specified by the identifier of the data is modulated based on the MCS determined by the adaptive modulation, and retransmitted the modulated data. Based on the MCS in which the error portion of one data is retained, data other than the error portion is demodulated on the basis of the MCS determined by adaptive modulation, and the demodulated error portion and the retained data are chase synthesized.

By such a configuration, the MCS of retransmission data and normal data is independently controlled, and the MCS suitable for the respective data is used, without departing from the standard, similarly to the wireless communication system, thereby effectively utilizing adaptive modulation and wireless communication. Stability improvement can be attained.

The component corresponding to the technical idea in the wireless communication system mentioned above, and its description can be applied also to the said transmission apparatus, the receiving apparatus, and the wireless communication method.

As described above, the wireless communication system of the present invention does not deviate from the standard, and independently controls the MCS of the retransmitted data and the normal data, and by using the MCS suitable for each data, the effective utilization of the adaptive modulation and the stability of the wireless communication are achieved. It becomes possible to aim at improvement.

1 is an explanatory diagram showing a schematic connection relationship of a wireless communication system.
2 is a block diagram showing a schematic configuration of a base station.
3 is a functional block diagram illustrating a hardware configuration of a PHS terminal.
4 is a perspective view showing the appearance of a PHS terminal.
5 is a flowchart showing the flow of processing in the radio communication method.
FIG. 6 is a block diagram for supplementary explanation of the flowchart of FIG. 5.
7 is an explanatory diagram for explaining a frame structure of data to be transmitted.
8 is an explanatory diagram for explaining the class of MCS.
9 is an explanatory diagram for explaining an error portion in a frame.
10 is an explanatory diagram for explaining the positional relationship between retransmission data and normal data.
11 is an explanatory diagram for explaining the operation of the chase synthesis.

Best Modes for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values and the like shown in these embodiments are only examples for facilitating understanding of the invention, and the invention is not limited except as specifically mentioned. In addition, in this specification and drawing, about the element which has substantially the same function and structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol, and the element which is not directly related to this invention omits illustration.

A mobile station represented by a PHS terminal, a cellular phone, or the like establishes a wireless communication system that communicates wirelessly with base stations fixedly arranged at predetermined intervals. The base station and the mobile station in such a wireless communication system function as a transmitting device and a receiving device for transmitting and receiving data to any station. In the present embodiment, the base station is described as the transmitting device and the mobile station as the receiving device for easy understanding, but needless to say, the opposite configuration is also established. Here, first, the entire wireless communication system will be described, and then, specific configurations of the PHS terminal as the base station and the mobile station will be described. In this embodiment, although the PHS terminal is held as a mobile station, the present invention is not limited to this case, but is not limited to a mobile phone, a notebook personal computer, a personal digital assistant (PDA), a digital camera, a music player, a car navigation system, a portable TV, and a game. Various electronic devices capable of wireless communication, such as equipment, DVD players, and remote controllers, can also be used as mobile stations.

(First Embodiment: Wireless Communication System 100)

1 is an explanatory diagram showing a schematic connection relationship of the wireless communication system 100. The wireless communication system 100 comprises a PHS terminal 110 (110A, 110B), a base station 120 (120A, 120B), an ISDN (Integrated Services Digital Network) line, the Internet, a dedicated network, etc. And a relay server 140.

In the wireless communication system 100, when a user connects a communication line from one's own PHS terminal 110A to another PHS terminal 110B, the PHS terminal 110A has a base station 120A within a communication range. Requests a wireless connection. The base station 120A, having received the radio connection request, requests the relay server 140 to communicate with the communication partner via the communication network 130, and the relay server 140 wirelessly communicates with the other PHS terminal 110B. For example, the base station 120B within the range is selected to secure the communication path between the base station 120A and the base station 120B, thereby establishing communication between the PHS terminal 110A and the PHS terminal 110B.

In such a wireless communication system 100, various techniques are employed to improve the communication speed and communication quality of the PHS terminal 110 and the base station 120. In the present embodiment, for example, next-generation PHS communication technologies such as ARIB STD T95 and PHS MoU are employed, and TDD (Time Division Duplex: Time Division Duplex) / is used between the PHS terminal 110 and the base station 120. Wireless communication based on the OFDMA (or TDD / OFDM) scheme is performed. In addition, adaptive modulation is also used in the wireless communication system 100, and the PHS terminal 110 and the base station 120 request MCSs from each other, thereby adaptively modulating the communication environment while maintaining communication quality. To improve the communication speed.

Under the FM-mode in the wireless communication system 100, only one type of MCS can be designated for one frame. However, since the retransmission of the error portion is performed at a predetermined frame timing, if both the transmitting apparatus and the receiving apparatus can identify the frame in which the error occurs and the error portion, and can identify the MCS used in the frame, The error part can be demodulated based on the desired MCS without placing the MCS. Therefore, it is possible to free the required area of the MCS to normal data (parts other than retransmission data in a frame), and the MCS based on adaptive modulation can be set to normal data. In this way, by independently controlling the MCS of the retransmitted data and the normal data, and using the MCS suitable for each data, it is possible to effectively utilize adaptive modulation and to improve the stability of wireless communication. Hereinafter, specific configurations and operations will be described.

(Base station 120)

2 is a block diagram showing a schematic configuration of the base station 120. The base station 120 includes a base station control unit 210, a base station memory 212, a base station wireless communication unit 214, and a base station wired communication unit 216.

The base station controller 210 manages and controls the entire base station 120 by a semiconductor integrated circuit including a central processing unit (CPU). In addition, the base station control unit 210 controls the communication connection of the PHS terminal 110 to the communication network 130 or another PHS terminal 110 by using a program of the base station memory 212.

The base station memory 212 includes a ROM, a RAM, an EEPROM, a nonvolatile RAM, a flash memory, a hard disk drive (HDD), and the like, and stores a program, time information, and the like processed by the base station controller 210.

The base station radio communication unit 214 establishes communication with the PHS terminal 110 to transmit and receive data. In addition, according to the communication quality with the PHS terminal 110, it is possible to determine the optimal MCS for efficient communication and request the PHS terminal 110.

The base station wired communication unit 216 may be connected to various servers including the relay server 140 through the communication network 130.

In the present embodiment, the base station radio communication unit 214 also functions as the transmission data holding unit 230, the data modulating unit 232, the data transmitting unit 234, and the HARQ receiving unit 236.

The transmission data holding unit 230 is capable of specifying a frame of data with an MCS identifier specifying data to be transmitted to which a cyclic redundancy check bit (CRC) is added, and an MCS that modulates the data. Maintain relative to frame identifier. In this embodiment, an "identifier" means the display which can uniquely identify it with a numerical value, an alphabet, and a symbol.

The data modulator 232 modulates data based on the held MCS, and generates a baseband signal. Here, the MCS is an MCS that is the same as the MCS required by the PHS terminal 110 or is inferior in modulation efficiency. With such a configuration, the data can be modulated based on an MCS that is less than or equal to the MCS requested by the PHS terminal 110 and the base station 120 can be modulated. The PHS terminal 110 and the base station 120 More stable wireless communication can be established by the optimal MCS of both devices.

When the HARQ request is made from the PHS terminal 110, the data modulator 232 stores the data held in the transmission data holding unit 230 specified by the frame identifier and the error part identifier as the target of the HARQ. The error portion (retransmission data) is modulated on the basis of the MCS held in the transmission data holding section 230, and other than the error portion (normal data) is modulated on the basis of the MCS determined by adaptive modulation. This modulation timing and the subsequent transmission timing are determined by the standard.

In addition, when the request for HARQ is received from the PHS terminal 110, the data modulator 232 may arrange an error portion of data retransmitted by HARQ at a predetermined position in the frame and modulate it. This configuration makes it possible to intensively arrange the PRUs of the same error portion in the MCS at a predetermined position irrespective of the arrangement or the number of error PRUs in the retransmitted frame, thereby reducing the burden of modulation processing. .

The data transmitter 234 transmits data in frame units modulated by the data modulator 232 and an MCS identifier capable of specifying an MCS. When the HARQ request is made from the PHS terminal 110, the data transmitter 234 is configured to determine the retransmitted data and the normal data modulated by the data modulator 232 in the wireless communication system 100. Resend at frame timing. The MCS identifier at this time usually indicates the MCS of data.

When HARQ is received from the PHS terminal 110, the HARQ receiver 236 extracts a frame identifier of an error data included in an anchor channel and an identifier of an error portion, and specifies the data and the error portion.

(PHS terminal 110)

3 is a functional block diagram showing the hardware configuration of the PHS terminal 110, and FIG. 4 is a perspective view showing the appearance of the PHS terminal 110. As shown in FIG. The PHS terminal 110 includes a terminal control unit 310, a terminal memory 312, a display unit 314, an operation unit 316, an audio input unit 318, an audio output unit 320, and a terminal radio. It is configured to include a communication unit 322.

The terminal controller 310 manages and controls the entire PHS terminal 110 by a semiconductor integrated circuit including a central processing unit (CPU). In addition, the terminal control unit 310 also performs a call function, a mail transmission / reception function, an imaging function, a music reproduction function, and a TV viewing function using a program in the terminal memory 312.

The terminal memory 312 includes a ROM, a RAM, an EEPROM, a nonvolatile RAM, a flash memory, an HDD, and the like, and stores a program, voice data, and the like processed by the terminal controller 310.

The display unit 314 is composed of a liquid crystal display, EL (Electro Luminescence) and the like, stored in the terminal memory 312 or provided from an application relay server (not shown) via the communication network 130, A graphical user interface (GUI) of the application can be displayed.

The operation unit 316 is composed of a switch such as a keyboard, a cross key, a joystick, and accepts a user's operation input.

The voice input unit 318 is composed of voice recognition means such as a microphone, and converts the voice of the user input at the time of communication into an electrical signal that can be processed in the PHS terminal 110.

The voice output unit 320 is configured of a speaker and converts the voice signal of the call partner received by the PHS terminal 110 into voice. In addition, an incoming sound, an operation sound of the operation unit 316, an alarm sound, and the like can also be output.

The terminal wireless communication unit 322 establishes wireless communication with the base station 120 in the communication network 130 to transmit and receive data. Upon establishing communication, the terminal wireless communication unit 322 transmits a Timing Control Channels (TCCH) including a synchronization signal to the base station 120, and the base station 120 samples the synchronization symbols from the TCCH. The transmission timing of the PHS terminal 110 is grasped and the difference is returned to the PHS terminal 110 using Synchronization Control Channels (SCCH).

In the present embodiment, the terminal wireless communication unit 322 includes a data receiver 330, a data demodulator 332, an error correcting unit 334, an error detector 336, a demodulated data holding unit 338, and HARQ. It also functions as a transmitter 340 and a chase synthesizer 342.

The data receiver 330 receives the data and the MCS identifier from the base station 120.

The data demodulator 332 demodulates the data based on the MCS specified by the MCS identifier received by the data receiver 330 and transmits the data to the error correction unit 334. In addition, when the PHS terminal 110 receives HARQ and then receives data including retransmission data at a predetermined frame timing, the data demodulator 332 demodulates the retransmission data of the received data. The demodulator is demodulated based on the MCS specified by the MCS identifier held by the holding unit 338, and the normal data is demodulated based on the MCS specified by the received MCS identifier and transmitted to the chase synthesis unit 342.

The error correction unit 334 performs error correction on the data transmitted from the data demodulation unit 332 or the chase synthesis unit 342 through the circuit redundancy check bit (CRC).

The error detection unit 336 detects an error that could not be corrected even by the error correction unit 334.

When the error detection unit 336 detects an error, the demodulation data holding unit 338 maintains the demodulated data and the MCS identifier of the data in association with the frame identifier.

When the error detector 336 detects an error, the HARQ transmitter 340 transmits an HARQ including the frame identifier of the data and the identifier of the error part to the base station 120. In this embodiment, since data in units of frames are alternately transmitted and received between the base station 120 by the TDD / OFDMA method, HARQ is transmitted using an anchor channel of transmission data to be transmitted to the base station 120. At this time, the request MR of the MCS set in the same anchor channel is the MCS based on normal adaptive modulation.

The chase synthesizing unit 342 performs chase combining on the retransmitted data demodulated by the data demodulating unit 332 and the data retained in the demodulation data holding unit 338 to the error correction unit 334. send.

In the wireless communication system 100 described above, both devices can correct errors by HARQ using two communication paths between the PHS terminal 110 and the base station 120. The optimal MCS can be used regardless of changes in the communication environment.

Next, a wireless communication method for performing wireless communication using the above-described PHS terminal 110 or base station 120 will be described.

(Wireless communication method)

FIG. 5 is a flowchart showing a flow of processing of the radio communication method, and FIG. 6 is a block diagram for supplementary explanation of the flowchart of FIG. 5.

First, the PHS terminal 110 requests the MCS through the anchor channel of the transmission data (S400), and the base station 120 determines the MCS of the data to be transmitted according to the requested MCS (S402). The base station 120 then temporarily holds the data to be transmitted and the MCS identifier of the MCS that modulates the data in the transmission data holding unit 230 in association with the frame identifier (S404). The data held in the transmission data holding unit 230 is held until a predetermined time that can be considered that HARQ has not occurred has elapsed.

7 is an explanatory diagram for explaining a frame structure of data to be transmitted. In OFDMA (or OFDM), a two-dimensional map is formed in the time axis direction and the frequency direction, and a plurality of channels 500 are arranged with a uniform baseband distance in the frequency axis direction, and in each channel 500, A PRU 510 is disposed for each TDMA slot 502. Therefore, the PRU 510 is defined as an occupied band of 900 kHz according to the baseband distance and a time length of 625 μsec by time division. The frame is composed of an anchor channel (ANCH) 520 related to the control signal and an extra channel (EXCH) 522 for storing data.

The anchor channel 520 is a FM-mode control signal and includes, for example, an Mcs Indicator (MI), an Mcs Requirement (MR), a map, and an ACK field. Here, MI represents the MCS identifier of the MCS when the base station 120 modulates data. The MR is an MCS request for data transmitted by itself. In terms of time, the MI indicates an MCS used for modulation of data transmitted simultaneously with the MCS identifier, and the MR indicates a desired MCS after the next time. Therefore, the MCS requested by the MR is reflected at least one frame later. In the HARQ of the present embodiment, the MR transmitted from the PHS terminal 110 to the base station 120 can use an MCS based on normal adaptive modulation regardless of the MCS of retransmission data, and the base station 120 MI from) can also use MCS of normal data.

In addition, the map exists only in the transmission frame from the base station 120 to the PHS terminal 110 and indicates the allocation of the extra channel 522. The ACK field indicates an error detection result of the demodulated data. When an error is detected, an ACK is stored. When an error is detected, an NACK and a bit string necessary for specifying the error portion are stored. The error detection unit represented by such a bit string may be for each PRU, or may be for one or a plurality of PRUs that are CRC detection units.

The extra channel 522 is a PRU assigned to each user as a call path in the FM-Mode, and can be assigned to a plurality of users. For example, in the example of FIG. 7, EXCH1 to EXCH10 indicated by diagonal lines are released to the user, and data is transmitted using the EXCH1 to EXCH10. This allocation of extra channels 522 is done through a carrier sense that determines whether the PRU is being used by another user. The assigned result is shown in the map of anchor channel 520 as described above.

Subsequently, the data modulator 232 of the base station 120 modulates the data using the MCS (S406), and the data transmitter 234 transmits the modulated data to the PHS terminal 110 (S408).

8 is an explanatory diagram for explaining a class of the MCS. In this embodiment, for example, 11 classes of MCSs are provided, and a modulation scheme and a coding scheme are prepared in each class. In Fig. 8, the higher the numerical value of the MCS identifier, the higher the modulation efficiency.

Subsequently, the data receiving unit 330 of the PHS terminal 110 receives the data and the MCS identifier from the base station 120 (S410). Then, the data demodulator 332 demodulates the data based on the MCS specified by the MCS identifier (S412), and the error correction unit 334 performs error correction of the data (S414). Here, the error detection unit 336 detects whether or not an error that cannot be corrected even by the error correction unit 334 remains in the data (S416), and returns an ACK to the base station 120 when there is no error. The data is transmitted to an upper layer (for example, the terminal controller 310) (S418).

If an error is detected in the error detection step (S416), the demodulation data holding unit 338 maintains the demodulated data and the MCS identifier of the data in association with the frame identifier (S420), and the HARQ transmitter 340 makes a NACK, a frame. The HARQ is transmitted using the ACK field including the identifier and the identifier of the error part (S422).

9 is an explanatory diagram for explaining an error portion in a frame. In the present embodiment, since the error detection unit is two PRUs, for example, even if there is an error in EXCH4 which is one PRU, the error portion is represented by EXCH3 and EXCH4 represented by cross hatching in the extra channel 522 of FIG. do. In this case, the identifiers of the error portions in the anchor channel 520 are, for example, "3" and "4".

In this HARQ transmission step (S422), the MCS of the frame in which the error has occurred is not transmitted to the PHS terminal 110. In the present embodiment, the MCS used in the frame is specified by specifying the frame and the error portion in which the error occurs in the PHS terminal 110 and the base station 120, so that the error portion is not based on the desired MCS even if the MCS is not placed on the HARQ. Can be demodulated. Therefore, the required area of the MCS can be released from the normal data, and the MCS based on the adaptive modulation can be set.

The HARQ receiver 236 of the base station 120 receives the HARQ (S424), and the data modulator 232 is held in the transmission data holding unit 230, which is specified by a frame identifier and an error part identifier of the ACK field. The error part (retransmission data) of the data is modulated after a predetermined frame based on the MCS held in the transmission data holding unit 230 (S426).

10 is an explanatory diagram for explaining the positional relationship between retransmission data and normal data. Designated as an error part from the PHS terminal 110 is EXCH3 and EXCH4 of the data, but among the frames to be retransmitted, the error part is placed at a predetermined position of the frame, here at the beginning (indicated by cross hatching in FIG. 10). . The other normal data is arranged after the retransmission data (indicated by the diagonal lines in FIG. 10).

Subsequently, the data transmitter 234 of the base station 120 transmits the modulated data to the PHS terminal 110 (S428), and when the data receiver 330 of the PHS terminal 110 receives the data (S430). The data demodulation section 332 demodulates the retransmission data of the received data based on the MCS held in the demodulation data holding section 338 at the prescribed HARQ timing, and normalizes the data to the MCS determined by adaptive modulation. Based on the demodulation (S432), the chase synthesis section 342 then chases the demodulated error portion and the data held in the demodulation data holding section (S434).

11 is an explanatory diagram for explaining the operation of the chase synthesis. When an error is detected in the data received and demodulated by the PHS terminal 110, only the error portion is transmitted to the base station 120 together with the NACK, and the demodulated data holding unit is not discarded without destroying the frame in which the error is detected. 338). When only the error portion is received from the base station 120 as the retransmission data 550, the PHS terminal 110 maximizes the data 552 held in the retransmission data 550 and the demodulation data holding unit 338. By combining by Maximum Ratio Combining (MRC), the reconstruction data 554 is generated. In such a chase synthesis method, the SINR of a received frame can be improved by the maximum ratio combining of data, and the error can be reduced efficiently.

The data in which the error portion is restored in this manner is repeated from the data correction step (S414) similarly to the data received initially, and finally transferred to the upper layer (S418).

In the wireless communication method described above, the MCS of the retransmission data and the normal data is independently controlled without departing from the standard, and the MCS suitable for each data is used to effectively utilize the adaptive modulation and improve the stability of the wireless communication. It becomes possible.

As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. If it is those skilled in the art, it is clear that various changes or modifications can be conceived within the range described in a claim, and it is understood that they belong naturally to the technical scope of this invention also.

In addition, it is not necessary to process each process in the wireless communication method of this specification in time series according to the order described as a flowchart, and the process performed in parallel or separately (for example, parallel process or process by an object). ) May also be included.

Although this invention was demonstrated in detail and with reference to the specific embodiment, it is clear for those skilled in the art that various changes and correction can be added without deviating from the mind and range of this invention.

This application is based on the JP Patent application-application number 2008-016972 of an application on January 28, 2008, The content is taken in here as a reference.

[Industrial Availability]

INDUSTRIAL APPLICABILITY The present invention can be used in a radio communication system, a transmission device, a reception device, and a radio communication method capable of radio communication by adaptive modulation (high speed adaptive modulation).

100: wireless communication system
110: PHS terminal
120: base station
230: transmission data holding unit
232: data modulation unit
234: data transmission unit
236 HARQ receiver
330: data receiving unit
332: data demodulator
334 error correction unit
336: error detection unit
338: demodulation data holding unit
340: HARQ transmitter
342: Chase synthesis unit
344: error transmission unit
520: anchor channel
522: Extra Channel

Claims (11)

On the basis of the MCS specified by the MCS identifier capable of wirelessly communicating with the transmitting device and receiving the MCS identifier capable of specifying the data of the frame unit modulated according to the MCS determined by the adaptive modulation and the MCS identifier. A wireless communication system comprising a receiving device for demodulating the received data.
The transmitting device,
A transmission data holding unit for holding the data to be transmitted and the MCS identifier of the MCS that modulates the data in association with a frame identifier that can be specified;
A data modulator for modulating the data based on the held MCS;
And a data transmitter for sequentially transmitting the modulated data.
The receiving device,
A data receiving unit for receiving data from the transmitting device;
A data demodulator for demodulating the received data;
An error detector for detecting an error of the demodulated data;
A demodulation data holding unit for holding the demodulated data and the MCS identifier of the data in association with the frame identifier when an error is detected in the demodulated data;
If an error is detected in the demodulated data, an ARQ transmitter for transmitting an ARQ (auto retransmission request) including a frame identifier of the data and an identifier of an error part,
The data modulator is held in the transmission data holding unit specified by a frame identifier of the ARQ and an identifier of an error part after a predetermined frame from reception of an ARQ relating to the data when an error is detected in the demodulated data. Modulating the error portion of the data based on the MCS held in the transmission data holding portion, and modulating other than the error portion based on the MCS determined by adaptive modulation,
The data transmitting unit transmits the error portion of the data modulated based on the MCS and data modulated based on the MCS determined by the adaptive modulation,
The data demodulation section demodulates the error portion of the received data based on the MCS determined by the adaptive modulation based on the MCS held by the demodulation data holding portion,
And the receiving device further comprises a chase synthesizing unit for chasing the demodulated error portion and the data held in the demodulated data holding unit. The method according to claim 1,
And the data modulating unit modulates an error portion of data retransmitted by ARQ at a predetermined position in a frame. The method according to claim 1,
The MCS in the data modulator is an MCS that is the same as the MCS requested by the receiver or is inferior in modulation efficiency. The method according to claim 1,
The radio communication system is a system based on ARIB STD T95 or PHS MoU, and the ARQ is a HARQ (Hybrid ARQ) in the radio communication system. The method according to claim 1,
The data modulator modulates data other than the error portion based on the MCS determined by adaptive modulation,
And the data demodulation unit demodulates data other than the error portion based on MCS determined by adaptive modulation. A transmitting device for transmitting data of a frame unit modulated based on an MCS determined by adaptive modulation and an MCS identifier capable of specifying the MCS to a receiving device,
A transmission data holding unit for holding the data to be transmitted and the MCS identifier of the MCS that modulates the data in association with a frame identifier that can be specified;
A data modulator for modulating the data based on the held MCS;
And a data transmitter for sequentially transmitting the modulated data.
When an ARQ (auto retransmission request) is received from the receiving device,
The data modulator is configured to receive an error portion designated by the receiver of data held in the transmission data holding unit specified by a frame identifier of the ARQ and an identifier of an error portion after a predetermined frame from the reception of the ARQ. Modulate according to the MCS maintained in
And the data transmitter retransmits the modulated data. The method of claim 6,
And the data modulator modulates data other than the error portion based on MCS determined by adaptive modulation. A receiving apparatus for receiving from a transmitting apparatus data of a frame unit modulated based on an MCS determined by adaptive modulation and an MCS identifier capable of specifying the MCS,
A data receiving unit for receiving data from the transmitting device;
A data demodulator for demodulating the received data;
An error detector for detecting an error of the demodulated data;
A demodulation data holding unit for holding the demodulated data and the MCS identifier of the data in association with the frame identifier when an error is detected in the demodulated data;
If an error is detected in the demodulated data, an ARQ transmitter for transmitting an ARQ (auto retransmission request) including a frame identifier of the data and an identifier of an error part,
The data demodulation unit demodulates an error portion of data received from the transmission device based on the MCS held in the demodulation data holding unit,
And a chase synthesizing unit for chasing the demodulated error portion and the data held in the demodulated data holding unit. The method according to claim 8,
And the data demodulation unit demodulates data other than the error part based on MCS determined by adaptive modulation. On the basis of the MCS specified by the MCS identifier capable of wirelessly communicating with the transmitting device and receiving the MCS identifier capable of specifying the data of the frame unit modulated according to the MCS determined by the adaptive modulation and the MCS identifier. A wireless communication method for performing wireless communication using a receiving device that demodulates the received data.
The transmitting device,
Maintain the data to be transmitted and the MCS identifier of the MCS that modulates that data in association with the frame identifier of the data,
Modulate the data based on the retained MCS,
Sequentially transmit the modulated data,
The receiving device,
Receiving data from the transmitting device,
Demodulating the received data;
Detecting an error of the demodulated data,
If an error is detected in the demodulated data, the demodulated data and an MCS identifier of the data are held in association with the frame identifier, and ARQ (auto retransmission request) including a frame identifier of the data and an identifier of an error part Send,
The transmitting device also,
After a predetermined frame from the reception of the ARQ, the error portion of the retained data specified by the frame identifier of the ARQ and the identifier of the error portion is modulated based on the retained MCS,
Retransmit the modulated data,
The receiving device also,
Demodulate the error portion of the received data based on the retained MCS,
And chase synthesizes the demodulated error portion and the retained data. The method according to claim 10,
The transmitting device also,
Modulates data other than the error portion based on MCS determined by adaptive modulation,
The receiving device also,
And demodulating data other than the error part based on MCS determined by adaptive modulation.

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